An undercut must be made in
each tree being felled. The undercut must be of a size so the tree will not split
and will fall in the intended direction. [29 CFR 1910.266(h)(2)(v)]

A backcut must be made in each
tree being felled. The backcut must leave sufficient hinge wood to hold the tree to
the stump during most of its fall so that the hinge is able to guide the tree's fall in
the intended direction. Except in Open Face felling, the backcut must be above the
level of the horizontal facecut in order to provide an adequate platform to prevent
kickback. [29 CFR 1910.266(h)(2)(vi)
and (vii)]